A037862 a(n)=(number of digits <=1)-(number of digits >1) in base 3 representation of n.

1, -1, 2, 2, 0, 0, 0, -2, 3, 3, 1, 3, 3, 1, 1, 1, -1, 1, 1, -1, 1, 1, -1, -1, -1, -3, 4, 4, 2, 4, 4, 2, 2, 2, 0, 4, 4, 2, 4, 4, 2, 2, 2, 0, 2, 2, 0, 2, 2, 0, 0, 0, -2, 2, 2, 0, 2, 2, 0, 0, 0, -2, 2, 2, 0, 2, 2, 0, 0, 0, -2, 0, 0, -2, 0, 0, -2, -2, -2, -4, 5, 5, 3

Offset

1,3

Links

Table of n, a(n) for n=1..83.

Maple

A037862 := proc(n)
    a := 0 ;
    dgs := convert(n, base, 3);
    for i from 1 to nops(dgs) do
        if op(i, dgs)<=1 then
            a := a+1 ;
        else
            a := a-1 ;
        end if;
    end do:
    a ;
end proc: # R. J. Mathar, Oct 16 2015

Mathematica

b3d[n_]:=Module[{idn=IntegerDigits[n, 3]}, Count[idn, _?(#<2&)]-Count[idn, _?(#>1&)]]; Array[b3d, 90] (* Harvey P. Dale, Nov 08 2011 *)

Crossrefs

Sequence in context: A054978 A129438 A125096 * A337113 A285244 A263148

Adjacent sequences: A037859 A037860 A037861 * A037863 A037864 A037865

Keyword

base,sign

Author

Clark Kimberling

Status

approved